tree 66e0a2bdf18e03c7dadba7c4c7b896533aa2e762
parent d55b5fdaf40846221d543937b786956e27837fda
author David Gibson <david@gibson.dropbear.id.au> 1131353973 -0800
committer Linus Torvalds <torvalds@g5.osdl.org> 1131378818 -0800

[PATCH] FUTEX_WAKE_OP: enhanced error handling

The code for FUTEX_WAKE_OP calls an arch callback,
futex_atomic_op_inuser().  That callback can return an error code, but
currently the caller assumes any error is EFAULT, and will try various
things to resolve the fault before eventually giving up with EFAULT
(regardless of the original error code).  This is not a theoretical case -
arch callbacks currently return -ENOSYS if the opcode they are given is
bogus.

This patch alters the code to detect non-EFAULT errors and return them
directly to the user.

Of course, whether -ENOSYS is the correct return value for the bogus opcode
case, or whether EINVAL would be more appropriate is another question.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jamie Lokier <jamie@shareable.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>